refactor: timing calculations into own class

app/services/timing_calculator.rb

@@ -0,0 +1,54 @@
+#--------------------------
+#
+# @class ConditionScheduleCalculator
+#
+# @desc Responsibility: calculates time between two dates, giving a :timing_direction:
+# The :timing_direction is whether we are calculating the number of days
+# _before_, _after_, or _on_ this day, starting from today.
+#
+# @author Ashley Engelund (ashley.engelund@gmail.com  weedySeaDragon @ github)
+# @date   2019-08-14
+#
+#--------------------------
+#
+class TimingCalculator
+
+
+  # Determine the number of days today is _away_from_ this date.
+  #
+  # @param this_date [Date] - the date to compare to today
+  # @param timing_direction [Symbol] - which 'direction' (before, after, on) to compare to today
+  # @return [Integer] - the number of days away from today, based on our :timing_direction
+  def self.days_today_is_away_from(this_date, timing_direction)
+    days_1st_date_is_from_2nd(Date.current, this_date, timing_direction)
+  end
+
+
+  # Determine the number of days :a_date is _away_from_ :second_date.
+  # The :timing_direction is whether we are calculating the number of days
+  # _before_, _after_, or _on_ this day, starting from :a_date.
+  #
+  # @param a_date [Date] - the starting date
+  # @param second_date [Date] - the date to compare to :a_date
+  # @param timing_direction [Symbol] - which 'direction' (before, after, on) to compare to :a_date
+  # @return [Integer] - the number of days separating the two dates, based on the :timing_direction
+  def self.days_1st_date_is_from_2nd(a_date, second_date, timing_direction)
+
+    day_num_to_check = 0 # default value
+
+    # We use .to_date to ensure that we're comparing and working with Dates, not Times, etc.
+    # If calling .to_date throws an exception, that's an exception that should be raised.
+
+    if timing_direction == ConditionSchedule.timing_before
+      # number of days that a_date is _before_ second_date
+      day_num_to_check = second_date.to_date - a_date.to_date
+
+    elsif timing_direction == ConditionSchedule.timing_after
+      # number of days that a_date is _after_ second_date
+      day_num_to_check = a_date.to_date - second_date.to_date
+    end
+
+    day_num_to_check.to_i
+  end
+
+end

spec/factories/condition_schedules.rb

@@ -0,0 +1,28 @@
+FactoryBot.define do
+
+  factory :condition_schedule do
+    timing { :on }
+  end
+
+
+  trait :after do
+    timing { :after }
+  end
+
+  trait :before do
+    timing { :before }
+  end
+
+  trait :on  do
+    timing { :on }
+  end
+
+  trait :every_day  do
+    timing { :every_day }
+  end
+
+  trait :monthly do
+    timing { :on_month_day }
+  end
+
+end

spec/services/timing_calculator_spec.rb

@@ -0,0 +1,130 @@
+require 'rails_helper'
+
+RSpec.describe TimingCalculator do
+
+
+  let(:timing_before) { ConditionSchedule.timing_before }
+  let(:timing_after) { ConditionSchedule.timing_after }
+  let(:timing_on) { ConditionSchedule.timing_on }
+
+
+  let(:nov_30) { Date.new(2018, 11, 30) }
+  let(:dec_1) { Date.new(2018, 12, 1) }
+  let(:dec_2) { Date.new(2018, 12, 2) }
+
+
+  around(:each) do |example|
+    Timecop.freeze(dec_1)
+    example.run
+    Timecop.return
+  end
+
+
+  describe '.days_a_date_is_away_from is the number of days today is _away_from_ this date.' do
+
+    describe 'timing_direction is before' do
+
+      it '1st is 1 day before 2nd date  = 1' do
+        expect(described_class.days_1st_date_is_from_2nd(nov_30, dec_1, timing_before)).to eq 1
+      end
+
+      it '1st = 2nd date  == 0' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_1, dec_1, timing_before)).to eq 0
+      end
+
+      it '1st date is 1 day after 2nd date  = -1' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_2, dec_1, timing_before)).to eq -1
+      end
+
+    end
+
+    context 'timing_direction is after' do
+
+      it '1st is 1 day before 2nd date  = -1' do
+        expect(described_class.days_1st_date_is_from_2nd(nov_30, dec_1, timing_after)).to eq -1
+      end
+
+      it '1st = 2nd date  == 0' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_1, dec_1, timing_after)).to eq 0
+      end
+
+      it '1st date is 1 day after 2nd date  = 1' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_2, dec_1, timing_after)).to eq 1
+      end
+
+    end
+
+
+    context 'timing_direction is on (always returns 0 days away; this means always check on the 2nd date no matter how many days away)' do
+
+      it '2nd date is 1 day before the date = 0' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_1, nov_30, timing_on)).to eq 0
+      end
+
+      it '2nd date is == the date = 0' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_1, dec_1, timing_on)).to eq 0
+      end
+
+      it '2nd date is 1 day after the date = 0' do
+        expect(described_class.days_1st_date_is_from_2nd(dec_1, dec_2, timing_on)).to eq 0
+      end
+
+    end
+
+  end
+
+
+  describe '.days_today_is_away_from(timing, some_date)' do
+
+    context 'timing_direction is before' do
+
+      it 'today is 1 day before the date = described_class.days_1st_date_is_from_2nd(Date.current, nov_30, timing_before)' do
+        expect(described_class.days_today_is_away_from(nov_30, timing_before)).to eq described_class.days_1st_date_is_from_2nd(dec_1, nov_30, timing_before)
+      end
+
+      it 'today = the date = described_class.days_1st_date_is_from_2nd(Date.current, dec_1, timing_before)' do
+        expect(described_class.days_today_is_away_from(dec_1, timing_before)).to eq described_class.days_1st_date_is_from_2nd(Date.current, dec_1, timing_before)
+      end
+
+      it 'today is 1 day after the date = described_class.days_1st_date_is_from_2nd(Date.current, dec_2, timing_before)' do
+        expect(described_class.days_today_is_away_from(dec_2, timing_before)).to eq described_class.days_1st_date_is_from_2nd(Date.current, dec_2, timing_before)
+      end
+
+    end
+
+    context 'timing_direction is after' do
+
+      it 'today is 1 day after the date = described_class.days_1st_date_is_from_2nd(Date.current, dec_2, timing_after)' do
+        expect(described_class.days_today_is_away_from(dec_2, timing_after)).to eq described_class.days_1st_date_is_from_2nd(Date.current, dec_2, timing_after)
+      end
+
+      it 'date is on today = described_class.days_1st_date_is_from_2nd(Date.current, dec_1, timing_after)' do
+        expect(described_class.days_today_is_away_from(dec_1, timing_after)).to eq described_class.days_1st_date_is_from_2nd(Date.current, dec_1, timing_after)
+      end
+
+      it 'today is 1 day before the date = described_class.days_1st_date_is_from_2nd(Date.current, nov_30, timing_after)' do
+        expect(described_class.days_today_is_away_from(nov_30, timing_after)).to eq described_class.days_1st_date_is_from_2nd(Date.current, nov_30, timing_after)
+      end
+
+    end
+
+
+    context 'timing_direction is on (always returns 0 days away; this means always check on today)' do
+
+      it 'date is 1 day before today = described_class.days_1st_date_is_from_2nd(Date.current, nov_30, timing_on)' do
+        expect(described_class.days_today_is_away_from(nov_30, timing_on)).to eq described_class.days_1st_date_is_from_2nd(Date.current, nov_30, timing_on)
+      end
+
+      it 'date is on today = described_class.days_1st_date_is_from_2nd(Date.current, dec_1, timing_on)' do
+        expect(described_class.days_today_is_away_from(dec_1, timing_on)).to eq described_class.days_1st_date_is_from_2nd(Date.current, dec_1, timing_on)
+      end
+
+      it 'date is 1 day after today = described_class.days_1st_date_is_from_2nd(Date.current, dec_2, timing_on)' do
+        expect(described_class.days_today_is_away_from(dec_2, timing_on)).to eq described_class.days_1st_date_is_from_2nd(Date.current, dec_2, timing_on)
+      end
+
+    end
+
+  end
+
+end